Testosterone relaxes rabbit coronary arteries and aorta

BACKGROUND

Until menopause, women appear to be protected from coronary heart disease. Evidence suggests that estrogen may play a role in the protection of the cardiovascular system by exerting a beneficial effect on risk factors such as cholesterol metabolism and by a direct effect on the coronary arteries. To date there has been no evidence linking testosterone with the occurrence of coronary heart disease. Testosterone may affect the cardiovascular system directly, thus partially explaining the difference in the incidence of coronary artery disease in men and premenopausal women. The purpose of this study was to assess the direct effect of testosterone and a number of testosterone analogues on rabbit coronary arteries and aorta in vitro.

METHODS AND RESULTS

Rings of coronary artery and aorta of adult male or nonpregnant female New Zealand White rabbits were suspended in organ baths containing Krebs solution; isometric tension then was measured. The response to testosterone was investigated in prostaglandin F2 alpha (PGF 2 alpha)- and KCl-contracted rings. The effects of endothelium and nitric oxide synthase, prostaglandin synthetase, and guanylate cyclase inhibition on testosterone-induced relaxation were investigated. The effects of ATP-sensitive potassium channels and potassium conductance were also assessed. Relaxing responses in the presence of aromatase inhibition and testosterone receptor blockade were performed. The relaxing responses to the testosterone analogues etiocholan-3 beta-ol-17-one, epiandrosterone, 17 beta-hydroxy-5 alpha-androst-1-en-3-one, androst-16-en-3-ol, and testosterone enanthanate were measured. Testosterone relaxed rabbit coronary arteries and aorta. There was no significant difference between the relaxation effect of testosterone with or without endothelium. Similar results were obtained from male and nonpregnant female rabbits. The relaxing response of testosterone in the coronary artery was significantly greater than in the aorta. The relaxing response of testosterone in the coronary artery was significantly reduced by the potassium channel inhibitor barium chloride but not by the ATP-sensitive potassium channel inhibitor glibenclamide. The relaxing response to testosterone was greater in PGF 2 alpha-contracted rings compared with KCl-contracted rings. Inhibitors of nitric oxide synthase, prostaglandin synthetase, and guanylate cyclase did not affect relaxation induced by testosterone. Inhibition of aromatase and testosterone receptors did not affect relaxation. Testosterone did not shift the rabbit coronary arterial calcium concentration-dependent contraction curves, whereas verapamil did. There were, however, significant differences in the relaxing response to testosterone compared with testosterone analogues. Testosterone was the most potent relaxing agent, suggesting that there may be a structure-function relation in the relaxing response.

CONCLUSIONS

Testosterone induces endothelium-independent relaxation in isolated rabbit coronary artery and aorta, which is neither mediated by prostaglandin I2 or cyclic GMP. Potassium conductance and potassium channels but not ATP-sensitive potassium channels may be involved partially in the mechanism of testosterone-induced relaxation. The in vitro relaxation is independent of sex and of a classic receptor. The coronary artery is significantly more sensitive to relaxation by testosterone than the aorta. Testosterone is a more potent relaxing agent of rabbit coronary artery than other testosterone analogues.

Role of lysosomes in physiological activities, diseases, and therapy

Long known as digestive organelles, lysosomes have now emerged as multifaceted centers responsible for degradation, nutrient sensing, and immunity. Growing evidence also implicates role of lysosome-related mechanisms in pathologic process. In this review, we discuss physiological function of lysosomes and, more importantly, how the homeostasis of lysosomes is disrupted in several diseases, including atherosclerosis, neurodegenerative diseases, autoimmune disorders, pancreatitis, lysosomal storage disorders, and malignant tumors. In atherosclerosis and Gaucher disease, dysfunction of lysosomes changes cytokine secretion from macrophages, partially through inflammasome activation. In neurodegenerative diseases, defect autophagy facilitates accumulation of toxic protein and dysfunctional organelles leading to neuron death. Lysosomal dysfunction has been demonstrated in pathology of pancreatitis. Abnormal autophagy activation or inhibition has been revealed in autoimmune disorders. In tumor microenvironment, malignant phenotypes, including tumorigenesis, growth regulation, invasion, drug resistance, and radiotherapy resistance, of tumor cells and behaviors of tumor-associated macrophages, fibroblasts, dendritic cells, and T cells are also mediated by lysosomes. Based on these findings, a series of therapeutic methods targeting lysosomal proteins and processes have been developed from bench to bedside. In a word, present researches corroborate lysosomes to be pivotal organelles for understanding pathology of atherosclerosis, neurodegenerative diseases, autoimmune disorders, pancreatitis, and lysosomal storage disorders, and malignant tumors and developing novel therapeutic strategies.

Overexpression of BCL2 blocks TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human lung cancer cells

The tumor necrosis factor (TNF) related apoptosis-inducing ligand (TRAIL or Apo2L) and its receptors are members of the tumor necrosis factor superfamily. TRAIL triggers apoptosis by binding to its two proapoptotic receptors DR4 and DR5, a process which is negatively regulated by binding of TRAIL to its two decoy receptors TRID and TRUNDD. Here, we show that TRAIL effectively induces apoptosis in H460 human non-small-cell lung carcinoma cells via cleavage of caspases 8, 9, 7, 3, and BID, release of cytochrome c from the mitochondria, and cleavage of poly (ADP-ribose) polymerase (PARP). However, overexpression of Bcl2 blocked TRAIL-induced apoptosis in H460 cells, which correlated with the Bcl2 protein levels. Importantly, the release of cytochrome c and cleavage of caspase 7 triggered by TRAIL were considerably blocked in Bcl2 overexpressing cells as compared to vector control cells. Moreover, inhibition of TRAIL-mediated cytochrome c release and caspase 7 activation by Bcl2 correlated with the inability of PARP to be cleaved and the inability of the Bcl2 transfectants to undergo apoptosis. Thus, these results suggest that Bcl2 can serve an anti-apoptotic function during TRAIL-dependent apoptosis by inhibiting the release of cytochrome c and activation of caspase 7, thereby blocking caspase 7-dependent cleavage of cellular substrates.

Familial hypobetalipoproteinemia: genetics and metabolism

Familial hypobetalipoproteinemia (FHBL), an autosomal dominant disorder, is defined as <5th percentile LDL-cholesterol or apolipoprotein (apo) B in the plasma. FHBL subjects are generally heterozygous and asymptomatic. Three genetic forms exist: (i) premature stop codon specifying mutations of APOB; (ii) FHBL linked to a susceptibility locus on the chromosome 3p21; and (iii) FHBL linked neither to APOB nor to the chromosome 3p21. In heterozygous apoB-defective FHBL, the hepatic VLDL export system is defective because apoB 100, the product of the normal allele, is produced at approximately 25% of normal rate, and truncated apoB is cleared too rapidly. The reduced capacity for hepatic triglyceride export increases hepatic fat three-fold. Indexes of adiposity and insulin action are similar to controls. 'Knock-in' mouse models of apoB truncations resemble human FHBL phenotypes. Liver fat in the chromosome 3p21-linked FHBL is normal. Elucidation of the genetic basis of the non-apoB FHBL could uncover attractive targets for lipid-lowering therapy. (See note added in proof.).

Evidence that the death receptor DR4 is a DNA damage-inducible, p53-regulated gene

DR4 (TRAIL-R1), a member of the tumor necrosis factor receptor superfamily, is a cell surface receptor that triggers the apoptotic machinery upon binding to its ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Although three other TRAIL receptors DR5, DcR1, and DcR2 are induced by DNA damage and are regulated by the wild-type p53 tumor suppressor, it was not known whether these factors also affect DR4 expression. In this study, we found that DR4 expression is also enhanced by DNA damage whether induced by ionizing radiation or by chemotherapeutic agents. The induction was observed predominantly in cells containing wild-type p53 and was similar to the regulation patterns of DR5 and Fas, two other members of the family which are known to be regulated by p53. Transfection of HPV 16 E6 gene into cells with wild-type p53, which decreased the level of p53 protein, resulted in suppression of DR4 induction by DNA-damaging agents. Conversely, introduction of exogenous wild-type p53 through adenovirus infection has led to upregulation of endogenous DR4 in cells with mutant p53. Moreover, the transcription inhibitor actinomycin D abolished DNA-damaging agent-induced DR4 expression. Thus, DR4 appears to be a DNA damage-inducible, p53-regulated gene.

Mechanisms of apoptosis induced by the synthetic retinoid CD437 in human non-small cell lung carcinoma cells

The novel synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) has been shown to induce apoptosis in various tumor cell lines including human non-small cell lung carcinoma (NSCLC) cells, which are resistant to the natural all-trans retinoic acid and to many synthetic receptor-selective retinoids. Although the mechanism of this effect was not elucidated, it was found to be independent of nuclear retinoid receptors. In the present study, we analysed the mechanisms by which CD437 induces apoptosis in two human NSCLC cell lines: H460 with wild-type p53 and H1792 with mutant p53. Both cell lines underwent apoptosis after exposure to CD437, although the cell line with wild-type p53 (H460) was more sensitive to the induction of apoptosis. CD437 increased the activity of caspase in both cell lines, however, the effect was much more pronounced in the H460 cells. The caspase inhibitors (Z-DEVD-FMK and Z-VAD-FMK) suppressed CD437-induced CPP32-like caspase activation and apoptosis in both cell lines. CD437 induced the expression of the p53 gene and its target genes, p21, Bax, and Killer/DR5, only in the H460 cells. These results suggest that CD437-induced apoptosis is more extensive in NSCLC cells that express wild-type p53, possibly due to the involvement of the p53 regulated genes Killer/DR5, and Bax although CD437 can also induce apoptosis by means of a p53-independent mechanism. Both pathways of CD437-induced apoptosis appear to involve activation of CPP32-like caspase.

Heart failure in rats causes changes in skeletal muscle morphology and gene expression that are not explained by reduced activity

In patients with congestive heart failure, skeletal muscle is characterized by a smaller proportion of slow-twitch oxidative fibers and reduced oxidative enzyme activity. However, whether these changes result from disuse or occur as a direct consequence of heart failure is unresolved. To address this issue, 18 rats with heart failure 8 weeks after left coronary artery ligation and 13 sham-operated control rats underwent quantification of locomotor activity by a photocell activation technique, measurements of hemodynamics and infarct size, histochemical and morphological analyses of the soleus and plantaris muscles, and Northern analyses of muscle contractile protein and oxidative enzyme mRNA expression. Although the rats with heart failure had elevated left ventricular end-diastolic pressures (24.1 +/- 2.6 mm Hg) and a mean infarct size of 35.1 +/- 4.1%, activity levels were similar to those found in the sham-operated rats (3849 +/- 304 versus 3526 +/- 130 counts per hour). With heart failure, there was a significant reduction of type I fibers in the soleus muscle and type IIa fibers in the plantaris muscle, with corresponding increases in intermediate staining of type IIab fibers in both muscles. This was associated with a 17% decrease in citrate synthase activity in both the soleus and plantaris muscles (26.2 +/- 1.6 versus 30.7 +/- 3.4 and 29.1 +/- 2.4 versus 35.7 +/- 3.4 mumol/L per minute per gram, respectively [P < .05]). In the soleus muscle, mRNA for both beta-myosin heavy chains and cytochrome C oxidase III (normalized to 18S RNA) was reduced (0.27 +/- 0.02 versus 0.65 +/- 0.02 and 0.23 +/- 0.04 versus 0.64 +/- 0.02 U), whereas the messages for IIx and IIb myosin heavy chains were increased. A similar decrease in messages for cytochrome oxidase and the primary myosin isoform was observed in the plantaris muscle. Both soleus beta-myosin heavy chain and cytochrome C oxidase expression show significant inverse relationships to left ventricular end-diastolic pressure and infarct size. In contrast, there was no relationship between either beta-myosin heavy chain or cytochrome C oxidase expression and locomotor activity. These results indicate that in rats heart failure produces changes in skeletal muscle gene expression at the pretranslational level that cannot be explained by inactivity.

Evidence that retinoic acid receptor beta induction by retinoids is important for tumor cell growth inhibition

Retinoic acid receptor beta (RARbeta) is thought to be involved in suppressing cell growth and tumorigenicity. Many premalignant and malignant cells exhibit a reduced RARbeta expression. However, in some of these cells (e.g. H157 human squamous cell carcinoma cells), RARbeta can be induced by retinoids (e.g. all-trans-retinoic acid, ATRA) because its promoter contains a retinoic acid response element. To examine the hypothesis that RARbeta induction is important for inhibition of cell proliferation by retinoids, we blocked ATRA-induced RARbeta expression in H157 cells using a retroviral vector harboring multiple copies of antisense RARbeta2 sequences. Antisense RARbeta-transfected cells showed not only decreased expression of ATRA-induced RARbeta protein but also reduced ATRA-induced RARE binding activity and transactivation. Importantly, all antisense RARbeta transfectants of H157 cells were less responsive than vector-transfected cells to the growth inhibitory effects of the retinoids ATRA and Ch55 in vitro. These results demonstrate that RARbeta induction may play an important role in mediating growth inhibitory effects of retinoids in cancer cells.

Traditional herbal medicine and nanomedicine: Converging disciplines to improve therapeutic efficacy and human health

Traditional herbal medicine (THM), an ancient science, is a gift from nature. For thousands of years, it has helped humans fight diseases and protect life, health, and reproduction. Nanomedicine, a newer discipline has evolved from exploitation of the unique nanoscale morphology and is widely used in diagnosis, imaging, drug delivery, and other biomedical fields. Although THM and nanomedicine differ greatly in time span and discipline dimensions, they are closely related and are even evolving toward integration and convergence. This review begins with the history and latest research progress of THM and nanomedicine, expounding their respective developmental trajectory. It then discusses the overlapping connectivity and relevance of the two fields, including nanoaggregates generated in herbal medicine decoctions, the application of nanotechnology in the delivery and treatment of natural active ingredients, and the influence of physiological regulatory capability of THM on the in vivo fate of nanoparticles. Finally, future development trends, challenges, and research directions are discussed.

Post-infarction heart failure in the rat is associated with distinct alterations in cardiac myocyte molecular phenotype

The myocardial molecular and cellular responses to hemodynamic and other hypertrophic stimuli have been characterized extensively, but less is known of the alterations in gene expression during the evolution of heart failure following myocardial infarction, and specifically those affecting the cardiac myocytes. Therefore, the present study was undertaken to test the hypothesis that post-infarction heart failure and remodeling in the rat is associated with a distinct myocyte molecular phenotype. To address this question, hemodynamic measurements were performed in vivo; and myocytes isolated from the non-infarcted myocardium 1 day, 1 week, and 6 weeks post-coronary artery ligation in post-infarct rats and sham controls. Myocyte size, mRNA levels for immediate early genes, contractile proteins, and sarcoplasmic reticulum Ca2+-ATPase (SERCA) and phospholamban were assayed by Northern analyses, and SERCA and phospholamban proteins were examined by Western blotting. Hemodynamic evidence of heart failure was present at all post-infarct time points. Myocyte size was increased significantly at 6 weeks. c-myc expression was increased at 1 day and 1 week in the infarcted rats, but returned to baseline by 6 weeks. Atrial natriuretic peptide and VEGF mRNAs were elevated at 1 and 6 weeks. Both beta-myosin heavy chain and skeletal alpha-actin expression were increased at all post-MI time points. In contrast, neither changes in the expression of the calcium-handling proteins (SERCA and phospholamban) were not observed, nor was there a change in TGFbeta1 or TGFbeta3. These results demonstrate that in rats with post-MI heart failure, there was an immediate induction of the fetal/embryonic transcriptional gene program which preceded myocyte hypertrophy and appeared to persist longer than in pressure-overload models. In further contrast to pressure-overload, expression of sarcoplasmic reticulum Ca2+-ATPase and phospholamban, was not altered despite a comparable degree of cellular hypertrophy and more severe hemodynamic decompensation. These findings suggest that there may be important differences in the regulatory mechanisms underlying these two forms of myocardial hypertrophy and heart failure.

Inhibition of mTOR complex 2 induces GSK3/FBXW7-dependent degradation of sterol regulatory element-binding protein 1 (SREBP1) and suppresses lipogenesis in cancer cells

Cancer cells feature increased de novo lipogenesis. Sterol regulatory element-binding protein 1 (SREBP1), when presented in its mature form (mSREBP1), enhances lipogenesis through increasing transcription of several of its target genes. Mammalian target of rapamycin (mTOR) complexes, mTORC1 and mTORC2, are master regulators of cellular survival, growth and metabolism. A role for mTORC1 in the regulation of SREBP1 activity has been suggested; however the connection between mTORC2 and SREBP1 has not been clearly established and hence is the focus of this study. mTOR kinase inhibitors (e.g., INK128), which inhibit both mTORC1 and mTORC2, decreased mSREBP1 levels in various cancer cell lines. Knockdown of rictor, but not raptor, also decreased mSREBP1. Consistently, reduced mSREBP1 levels were detected in cells deficient in rictor or Sin1 compared to parent or rictor-deficient cells with re-expression of ectopic rictor. Hence it is mTORC2 inhibition that causes mSREBP1 reduction. As a result, expression of the mSREBP1 target genes acetyl-CoA carboxylase and fatty acid synthase was suppressed, accompanied with suppressed lipogenesis in cells exposed to INK128. Moreover, mSREBP1 stability was reduced in cells treated with INK128 or rictor knockdown. Inhibition of proteasome, GSK3 or the E3 ubiquitin ligase, FBXW7, prevented mSREBP1 reduction induced by mTORC2 inhibition. Thus mTORC2 inhibition clearly facilitates GSK3-dependent, FBXW7-mediated mSREBP1 degradation, leading to mSREBP1 reduction. Accordingly, we conclude that mTORC2 positively regulates mSREBP1 stability and lipogenesis. Our findings reveal a novel biological function of mTORC2 in the regulation of lipogenesis and warrant further study in this direction.

Induction of apoptosis in human non-small cell lung carcinoma cells by the novel synthetic retinoid CD437

Retinoids are promising agents for the prevention and treatment of several human malignancies including lung cancer. However, many lung cancer cell lines are resistant to the growth inhibitory effects of all-trans-retinoic acid (ATRA). Recently, we found that a new synthetic retinoid, 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437), which binds selectively to nuclear RA receptor gamma, was the most effective inhibitor of the growth of human non-small cell lung carcinoma (NSCLC) cells among 37 retinoids tested. After a 4-day treatment with CD437 the growth of 8 NSCLC cell lines was inhibited with an IC50 ranging from 0.13 to 0.53 microM. In contrast, ATRA failed to inhibit the growth of any of these cell lines by more than 43% after a 7-day treatment even at 10 microM. The presence of detached rounded cells in treated cultures indicated that CD437 may induce apoptosis. Indeed, this was confirmed by the presence of 20-57% cells with a sub-G1 DNA content and by an enzyme-linked immunosorbent assay (ELISA) of apoptosis. Two retinoids, CD2366 and CD2665, which are antagonists of nuclear retinoid receptor activation, failed to inhibit the effect of CD437 on the growth of the NSCLC cell lines. CD437 failed to suppress the transcriptional activation of the activator protein-1 (AP-1) reporter. These results demonstrate that CD437 can induce apoptosis in NSCLC cells that are resistant to ATRA and that this effect is mediated by a mechanism that may be independent of transactivation of retinoid receptors or transrepression of AP-1.

Implication of multiple mechanisms in apoptosis induced by the synthetic retinoid CD437 in human prostate carcinoma cells

The synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) induces apoptosis in several types of cancer cell. CD437 inhibited the growth of both androgen-dependent and -independent human prostate carcinoma (HPC) cells in a concentration-dependent manner by rapid induction of apoptosis. CD437 was more effective in killing androgen-independent HPC cells such as DU145 and PC-3 than the androgen-dependent LNCaP cells. The caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK blocked apoptosis induced by CD437 in DU145 and LNCaP cells, in which increased caspase-3 activity and PARP cleavage were observed, but not in PC-3 cells, in which CD437 did not induce caspase-3 activation and PARP cleavage. Thus, CD437 can induce either caspase-dependent or caspase-independent apoptosis in HPC cells. CD437 increased the expression of c-Myc, c-Jun, c-Fos, and death receptors DR4, DR5 and Fas. CD437's potency in apoptosis induction in the different cell lines was correlated with its effects on the expression of oncogenes and death receptors, thus implicating these genes in CD437-induced apoptosis in HPC cells. However, the importance and contribution of each of these genes in different HPC cell lines may vary. Because CD437 induced the expression of DR4, DR5 and Fas, we examined the effects of combining CD437 and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and Fas ligand, respectively, in HPC cells. We found synergistic induction of apoptosis, highlighting the importance of the modulation of these death receptors in CD437-induced apoptosis in HPC cells. This result also suggests a potential strategy of using CD437 with TRAIL for treatment of HPC. Oncogene (2000) 19, 4513 - 4522.

Dual mechanisms of action of the retinoid CD437: nuclear retinoic acid receptor-mediated suppression of squamous differentiation and receptor-independent induction of apoptosis in UMSCC22B human head and neck squamous cell carcinoma cells

The synthetic retinoid 6-[3-(adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437), which can bind to and activate the nuclear retinoic acid receptors beta and gamma (RARbeta/gamma), is a potent inducer of apoptosis in various cancer cell lines. However, this effect was reported to be independent of RARs. In this study, we compared and contrasted the potencies and mechanisms of action of CD437 and several other receptor-selective retinoids in induction of apoptosis and modulation of squamous differentiation in UMSCC22B human head and neck squamous cell carcinoma cell line. CD437 and the structurally related retinoid CD2325 exhibited almost equal potency in inducing apoptosis, whereas several other retinoids failed to induce apoptosis. The RAR-specific pan antagonist AGN193109 failed to suppress CD437-induced apoptosis, indicating that the induction of apoptosis by CD437 was RAR-independent. c-Fos expression was induced by CD437 and CD2325 that induced apoptosis in the cell line but not by other retinoids that failed to induce apoptosis, suggesting a role for c-Fos in CD437-induced apoptosis. At low concentration (0.01 microM), CD437 shared with several other receptor-selective retinoids the ability to suppress the mRNA levels of the squamous differentiation markers Spr1, involucrin, and cytokeratin 1. This effect of CD437 could be blocked by AGN193109. We conclude that CD437 can exert its effects in UMSCC22B human human head and neck squamous cell carcinoma cells by at least two mechanisms: RAR-mediated suppression of squamous differentiation and RAR-independent induction of apoptosis.

Cytokine expression increases in nonmyocytes from rats with postinfarction heart failure

Growing evidence suggests that cardiac nonmyocyte cells may play an important regulatory role in the response to myocardial overload and injury via altered expression of paracrine products, such as cytokines and growth factors, but information concerning the cell-specific changes in the expression of these substances in heart-failure models is limited. Therefore, cardiac nonmyocytes were isolated from rats 1 day and 1 and 6 wk after left coronary artery ligation with resulting hemodynamic evidence of heart failure and in sham-operated control animals. mRNAs for tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, transforming growth factors (TGF)-beta1 and TGF-beta3, and type I and type III collagen were measured by Northern analyses. The temporal and quantitative relationships between the expression of these cytokines and collagen and myocyte hypertrophy were determined. mRNA expression of IL-1beta was increased by 1.3-fold at 1 day and 1 wk, and expression of TNF-alpha, IL-1beta, IL-6, TGF-beta1, and TGF-beta3 were increased by 1.4- to 2.1-fold at the 1-wk time point before returning toward baseline at 6 wk. There were significant correlations between the expression of these cytokines and the expression of types I and III collagen, which also peaked at 1 wk. Myocyte hypertrophy was seen first at 6 wk. These observations are consistent with a hypothesis that nonmyocyte cells play a regulatory role in the extracellular matrix changes during postinfarction remodeling and highlight the importance of examining cell-specific changes in gene expression and elucidating the role of cell-to-cell interactions within the myocardium.

Nanocrystals based pulmonary inhalation delivery system: advance and challenge

Pulmonary inhalation administration is an ideal approach to locally treat lung disease and to achieve systemic administration for other diseases. However, the complex nature of the structural characteristics of the lungs often results in the difficulty in the development of lung inhalation preparations. Nanocrystals technology provides a potential formulation strategy for the pulmonary delivery of poorly soluble drugs, owing to the decreased particle size of drug, which is a potential approach to overcome the physiological barrier existing in the lungs and significantly increased bioavailability of drugs. The pulmonary inhalation administration has attracted considerable attentions in recent years. This review discusses the barriers for pulmonary drug delivery and the recent advance of the nanocrystals in pulmonary inhalation delivery. The presence of nanocrystals opens up new prospects for the development of novel pulmonary delivery system. The particle size control, physical instability, potential cytotoxicity, and clearance mechanism of inhaled nanocrystals based formulations are the major considerations in formulation development.

Cellulose nanocrystals based clove oil Pickering emulsion for enhanced antibacterial activity

An effective antibacterial system was developed by using clove essential oil Pickering emulsion (CO-PE). The carboxymethyl cellulose sodium modified cellulose nanocrystals (CNC) was used as the stabilizer of CO-PE, which were prepared by environmentally friendly approach of homogenization technology. The factors affecting the formation and stability of CO-PE were studied, such as CNC concentration, homogenization pressure, CO concentration and ionic concentration and pH. And the antibacterial performance of CO-PE against E. coli and S. aureus was investigated by determining the minimal inhibitory concentration (MIC). The results showed that 1% CNC stabilized CO-PE exhibited small droplet size and rough surface, and had good stability at high pH values or salt concentration, owing to the presence of CNC on interface of droplet. And the CNC-stabilized CO-PE exhibited higher antimicrobial activity at equivalent CO concentration, which might be attributed to efficiently adhere to bacterial membrane. Therefore, our research would provide new insights for antibacterial application of Pickering emulsions loading essential oils in the food and other industries.

Expression of skeletal muscle sarcoplasmic reticulum calcium-ATPase is reduced in rats with postinfarction heart failure

OBJECTIVE

To determine whether heart failure in rats is associated with altered expression of the skeletal muscle sarcoplasmic reticulum Ca2+-ATPase (SERCA).

METHODS

SERCA protein and mRNA were examined in the soleus muscles of eight female rats with heart failure induced by coronary artery ligation, six weeks after the procedure (mean (SEM) left ventricular end diastolic pressure 20.4 (2.2) mm Hg) and in six sham operated controls by western and northern analyses, respectively.

RESULTS

SERCA-2a isoform protein was reduced by 16% (112 000 (4000) v 134 000 (2000) arbitrary units, p < 0.001), and SERCA-2a messenger RNA was reduced by 59% (0.24 (0. 06) v 0.58 (0.02) arbitrary units, p < 0.001). Although rats with heart failure had smaller muscles (0.54 mg/g v 0.66 mg/g body weight), no difference in locomotor activity was observed.

CONCLUSIONS

These results may explain the previously documented abnormalities in calcium handling in skeletal muscle from animals with the same model of congestive heart failure, and could be responsible for the accelerated muscle fatigue characteristic of patients with heart failure.

Novel nanocrystal-based solid dispersion with high drug loading, enhanced dissolution, and bioavailability of andrographolide

Objective

The current study sought to design a quickly dissolving, high drug loading nanocrystal-based solid dispersion (NC-SD) in order to improve the dissolution of poorly soluble drugs.

Methods

The NC-SD was prepared by means of combination of homogenization and spray-drying. Polymer hydroxypropylmethylcellulose (HPMC) was used as baseline dispersant for NC-SD of the model drug – andrographolide (AG). Three superdisintegrants cohomogenized with HPMC were used as codispersant for AG-NC-SD and compared to common water-soluble dispersants – mannitol and lactose. The dissolution characterization and oral bioavailability of AG-NC-SD were evaluated.

Results

The AG-NC-SD with the higher concentration of HPMC exhibited fast dissolution due to the enhanced wettability of HPMC. The water-soluble codispersants (mannitol and lactose) did not completely prevent AG-NC from aggregation during spray-drying. To achieve much faster AG release, cohomogenized superdisintegrants at a level of 20% must be used along with 25% HPMC. Compared with water-soluble dispersants like mannitol and lactose, superdisintegrants with high swelling capacity were much more effective dispersants for enhancing fast redispersion/dissolution of AG-NC-SD via a swelling-triggered erosion/disintegration mechanism. Surfactant-free AG-NC-SD with 15% cohomogenized sodium carboxymethyl starch combined with 15% HPMC and 10% lactose enhanced the dissolution further, without comprising drug loading, exhibited a barely compromised dissolution rate compared to precursor NC suspensions (f₂>50), and possessed drug loading up to 67.83%±1.26%. The pharmacokinetics results also demonstrated that the AG-NC-SD significantly improved the bioavailability in vivo of AG (P<0.05), compared with to the coarse AG.

Conclusion

This study illustrates that a quickly dissolving, high drug load, surfactant-free NC-SD can be prepared by using a superdisintegrant as codispersant, and provides a feasible strategy to improve the oral bioavailability of poorly soluble drugs.

Evaluation of exogenous surfactant treatment strategies in an adult model of acute lung injury

Two exogenous surfactant preparations [Survanta and bovine lipid extract surfactant (BLES)] were evaluated in saline lavage-injured adult sheep with two different delivery methods (instillation vs. aerosolization). Instilled BLES resulted in the greatest improvement in lung function, followed by aerosolized Survanta and then instilled Survanta. Aerosolized BLES was ineffective. Total surfactant recovery and distribution patterns were similar for Survanta and BLES for each delivery method tested. There were significant differences, however, in the proportion of surfactant recovered in the alveolar wash relative to the lung tissue between the groups at killing. Moreover, the ratio of poorly functioning small surfactant aggregates to superior functioning large aggregates isolated from alveolar wash samples correlated with the physiological responses. The calculated contribution of secreted endogenous surfactant to the total alveolar phospholipid pool at killing was significantly greater for the aerosolized Survanta group compared with the aerosolized BLES group. This finding suggested that there were differences in the interaction of the exogenous surfactants and their alveolar environments. We conclude that the response to exogenous surfactant in acute lung injury depends not only on the preparation used but also on how the surfactants are delivered to the injured lung.

Design and Evaluation of Novel Solid Self-Nanodispersion Delivery System for Andrographolide

Poorly water-soluble drugs offer challenges in developing a formulation product with adequate bioavailability. This study took advantage of the features of nanocrystals and direct compression technologies to develop a novel solid self-nanodispersion delivery system for andrographolide (Andro) in order to increase its dissolution rate for enhancing bioavailability. Andro nanosuspensions (Andro-NS) with a particle size of about 500 nm were prepared by homogenization technology and further converted into dried nanocrystal particles (Andro-NP) via spray-drying. The solid self-nanodispersion delivery system (Andro-SNDS)-loaded Andro-NP was prepared via direct compression technology. The DSC and PXRD results demonstrated that the Andro nanocrystals retained its original crystallinity. The dissolution of the Andro-SNDS formulation was 85.87% in pure water over 30 min, better than those of the coarse Andro and physical mixture of Andro and stabilizer. And the C _max (299.32 ± 78.54 ng/mL) and AUC_0-∞ (4440.55 ± 764.13 mg/L · h) of the Andro-SNDS formulation were significantly higher (p < 0.05) than those of the crude Andro (77.52 ± 31.73 ng/mL and 1437.79 ± 354.25 mg/L · h). The AUC of the Andro-SNDS was 3.09 times as high as that of the crude Andro. This study illustrated a novel approach to combine the features of nanocrystals and composite particles used to improve oral bioavailability of poorly soluble drug.